We originally went for bdb but encountered problems hence we switched to
using ldbm. I can't recall what it was, don't have the log anymore.
Presuming the openldap version is correct. What should I do next ?

The version number you gave is bogus. Given that -V isn't supported, I'm
even more inclined to believe OpenLDAP 2.0.2x which is what RedHat ships
with everything prior to RH ES4. Which means you are running on an
OpenLDAP release that is not supported, is horribly ancient, and has a very
unreliable backend (ldbm). BDB may be a little more work to set up
initially, but what you get is a stability that simply doesn't exist in
LDBM. If you want to stick with 2.0, that is your decision, but I have no
interest in answering any further questions about it, although others on
the list might.

"These censorship operations against schools and libraries are stronger
than ever in the present religio-political climate. They often focus on
fantasy and sf books, which foster that deadly enemy to bigotry and blind
faith, the imagination." -- Ursula K. Le Guin